Fluid impact pulverizer and separator



Jan. 6, 1953 A. M. ANDRIES 2,524,515

FLUID IMPACT PULVERIZER AND SEPARATOR Filed Jan. 4, 1949 2 SHEETS-SHEET2 fig. 5.

INVENTOR ,4/Fonse M/in dries Patented Jan. 6, 1953 FLUID IMPACTPULVERIZER AND SEPARATOR Alfonse M. Andries, Columbus, Ohio, assignor toBlaw-Knox Company, Pittsburgh, Pa., a corporation of New JerseyApplication January 4, 1949, Serial No. 69,103

This invention relates to mills of the impact pulverizer type. Moreparticularly, it relates to a mill in which streams of a gaseousatmosphere in which coal or coke is suspended are directed toward acommon point to cause the comminution of such material to desiredparticle size.

In general, such pulverizers produce fine grinding of such solidmaterial by turbulence in the gaseous atmosphere carrying the fragmentsof such material or by the colliding action of the streams within theapparatus carrying such material. Thus particles may collide with oneanother when moving in opposite or converging directions or may collidewith some portion of the apparatus and thus be subject to fracture.Further, such particles may impinge upon one another or upon a portionof the apparatus with glancing blows and be reduced in size byattrition.

In mills of the type with which this invention is concerned, theseparticles are entrained in the gaseous atmosphere by jets or ejectorsdirected so as to have a common intersection. In order to grind to asufiicient degree of fineness, the coarser particles are recirculated tosuch jets until reduced to the desired degree. The gaseous atmosphere isproduced and maintained as the consequence of the operation of the jetswith superheated steam or compressed air. These gaseous fluids,inclusive of such vapors as may be present, inspirate the particles ofcoal, coke or other solid fuel to be ground and cause them to besuspended in the streams of gaseous fluid and particles so created.

In this invention more efficient provision is made for feeding freshcoal or coke fragments and recirculating too coarse ground particles tothe grinding jets and for separating pulverulent material meetingspecification without excessive rejection. Further, in the mill of thisinvention a wide range of such fuels of different character can beground to predetermined particle size. Other objectsand advantages ofthis invention will be apparent from the following description and fromthe drawings, in which,

Figure 1 is a vertical view in cross section of a mill made inaccordance with this invention including the separator associatedtherewith;

Figure 2 is a view in cross section taken along line IIII of Figure 1;

Figure 3 is a view in cross section taken along line II[--III of Figure1;

Figure 4 is a view in cross section of the separator taken along lineIV--IV of Figure 1;

Figure 5 is a view in cross section taken along line VV of Figure 2; and

Figure 6 is a vertical view in cross section taken along line VIVI ofFigure 4.

6 Claims. (01. 24139) Referring to the preferred embodiment shown inFigures 1 to 6, a cylindrical casing I0 is composed of a number ofringlike sections either bolted or welded together in leakproof fashion.Casing l0 together with bottom I! and a top plate l2 define a grindingchamber L? in which there is a false bottom l4. Around the lowermostsection of casing I0 there are four circular openings l5 through each ofwhich a nozzle l6 projects. Each nozzle 6 is held in a block threadablyconnected to a plate |8 which is bolted in sealed engagement with anannular rim l9 welded to casing l9 around each opening l5. Superheatedsteam or compressed air is supplied to nozzles I6 through the respectivepipes 29. i For grinding coal compressed air is usually supplied tonozzles l6. Nozzles l6 are horizontally directed toward a commonintersection, the point center of which lies on the vertical axis ofchamber l3.

Each nozzle H5 is provided with a coaxially positioned barrel 2|pointing toward said common intersection and spaced in advance of therespective nozzle iii an amount which provides an annular inlet 22 whichconstitutes part of the inspiration zone for each grinding jet orejector comprising a nozzle l6 and its attendant barrel 2|. Each barrel2| is afiixed and held in place by set screws 2| in the bore of abracket 23 fastened to bottom I 4.

A circular baiiie plate 24 is located in a horizontal plane above therespective barrels 2|, where it is held in place over said barrels bylegs 25. Each leg 25 is welded or otherwise fastened respectively to abarrel 2| and baflie plate 24. A wear plate 25 is aflixed to baiile 24on the top side thereof in the center to prevent undue wear of baffle24.

Four pairs of curved vanes 26 are afiixed to the top of bafile 24 in anupstanding position. They form a series of four channels 21, the axis ofeach of which overlies the axis of its respective barrel 2|. In plan,vanes 26 outline a set of four cusps or foils arranged around wear plate25, the bases and peaks of which cusps are open. Hence, solid materialimpinging on wear plate 25 is guided by such channels to theirrespective inspiration zones 22 adjacent the open delivery end of eachchannel. Since adjacent vanes of adjacent cusps practically touch attheir inner ends, the likelihood of material moving over the top ofbafile 24 other than in one of the channels is minimized. The walls ofthe channels may, of course, be straight vanes converging toward eachother at the outer ends thereof. The height of suchvanes 26 isproportioned to the forces encountered.

A housing 28 is located in the center of the top of plate l2. Thehousing supports a nozzle block 29 in which a nozzle 30 is threaded.Housing 28 also supports a barrel 3| projecting downwardly through plateI2 at right angles to wear plate 25. Barrel 3| is spaced from nozzle 39to provide an annular inlet 32 which is part of the inspiration zone forthe feed jet or feed ejector which comprises nozzle 30 and barrel 3|.Gaseous fluid to operate nozzle 30 is supplied through a line 33. I havefound it advantageous to provide the channels 2'! on baffle plate 24,although the combination, broadly, of a wear plate and vanes adjacent abaille interposed between the common intersection of the recirculatingejectors and the feed ejector is a part, not of this invention, but ofthe invention shown and claimed in United States patent application,Serial No. 69,127, filed on even date herewith, in the name of WilliamMayo Venable.

Housing 23 has an opening on one side thereof adjacent inspiration zone32 to which opening there is connected a feed conduit 34. A bracket 35fastened to the edge of plate i2 supports conduit 34. for connection toa flared hopper 35 to which fresh material is supplied. A screw conveyor37 is rotatably supported in conduit 34 and is turned by a sprocket 38on the shaft thereof for material advancing engagement with the insideof conduit 34. Intermediate the ends of conduit 34 in advance of hopper35 there is a pipe connection 39 leading to a separator. Other feedingmeans for supplying solid material to inspiration zone 32 or directlyinto chamber l3 may also be used.

Entrained ground material when sufiiciently fine enough leaves chamberl3 borne by the gaseous fluid passing through chamber i3 and out throughan outlet comprising a pair of uptakes 40. These uptakes are joined attheir upper ends by a separator 4|. Separator 4| comprises a funnellikeouter annular passage 42 and a concentric inner passage 43. Thesepassages open into each other at their respective upper ends through anopening 44 in which there are curved directing vanes 45 to impart rotarymotion in one direction about the vertical axis of separator M to thestream of gaseous fluid and entrained ground material rising in passage42. The top of both passages is closed by a plate 46 in the center ofwhich there is a riser pipe 47 which projects downwardly into innerpassage 43 below opening 44. A bell type shield 48 is suspended bybrackets from the lower end of riser 41,

An inner funnel 53, substantially in the form of an inverted cone, issuspended in the upper flared portion of inner passage 43 substantiallyat the level of the lower end of riser 41. A horizontal and tangentialconduit 51 passes through outer passage 42 and opens into inner passage43 between the circular wall thereof and the exterior of funnel 50.Gaseous fluid, preferably superheated steam, is fed into conduit 5!through an inlet 52 supported in cap plate 53 which closes the outer endof conduit 5 I. The gaseous fluid is supplied to inlet 52 by a pipe 54.The horizontal direction of rotation of the gaseous fluid issuing frominlet 52 is the same direction of rotation as that imparted by vanes 45to the stream passing through opening 44 from passage 42. Hence,additional momentum of such stream is created in separator 4| resultingin more solid material passing upwardly in riser 41 while suspended inthega-seous fluid than would otherwise be the case, and therebyincreasing the. capacity of the The outer end of conduit 3d is openedmill. Such pulverulent material rising in riser 41 includes allparticles of a predetermined siz or less and avoids any unduly narrowrange of material capable of suspension and upward removal within innerpassage 43 through riser 4?. Thus, the heavier material of largerparticle size passing downwardly through funnel 5G in passage 43 andinto a downcomer 55 is kept to a minimum commensurate with the sizewhich the pulverulent material must not exceed. Since downcomer 55 isconnected to pipe 39 by a sleeve 56, such ground material rejected byseparator 4| is returned to conduit 34 where it is admixed with thefresh material being fed to inspiration zone 32 whence it isrecirculated and reground until it meets specification.

It is evident that the proportions of the various parts and openings ofapparatus made in accordance with this invention are matters within thescope of engineering skill. Thus the proportions of the vanes 26,uptakes e0, separator 41 and its parts and of the feeding mechanism willbe determined in the light of the particular character of the fuel to beground, the nature of the gaseous fluid or fluids used in the respectivejets, the pressures, temperatures and the like to be encountered and thesize of the apparatus. Such particulars constitute the field of processengineering and in such connection all of the drawings in this case areto be considered as merely diagrammatic. All portions of the apparatuswill also be suitably insulated where necessary to prevent undue loss ofheat.

Although I have illustrated and described but a preferred practice andembodiment of the invention, it will be recognized that changes in theprocedure and structural details may be made without departing from thespirit of the invention or the scope of the appended claims.

I claim:

1. Apparatus for pulverizing and separating material comprising incombination, a substantially open impact pulverizing chamber, aplurality of opposed generally horizontal grinding and recirculatingejectors having a common intersection in said chamber, an ejector forfeeding material into said chamber, said ejector being substantiallydirected toward said plurality of recirculating ejectors, a battleinterposed between said recirculating ejectors and said feeding ejector,said bafile being above said common intersection, pairs of upstandingwalls on said bafile on the side away from said recirculating ejectors,said walls forming radial channels which narrow as the distance from thecenter of the bafile increases, an outlet end for each channel beingpositioned substantially adjacent one of said recirculating ejectors, atleast one uptake connected to said chamber, a separator connected tosaid uptake to remove pulverulent material from, the stream in saiduptake, a downcomer to lead off rejected material from said stream,mechanical means for feeding material to said feed ing ejector, saidmechanical means being connected to said downcomer to receive thematerial passing therethrough, whereby said recirculating ejectors arecontinuously supplied with fresh and recirculated material guided bysaid channels.

2. Apparatus for pulverizing and separating material comprising incombination, an open grinding chamber, a plurality of opposed generallyhorizontal grinding jets having a common intersection in said chamber, ahorizontal bafile positioned above said common intersection andsubstantially covering the area between said jets,

curved upstanding vanes forming a, series of cusps around the center ofsaid baflle on the side away from said jets, said cusps being open atthe respective bases and peaks thereof and coinciding with the axes ofsaid jets, a. feed jet directed at said baflie adjacent and between saidbases, at least one uptake around the periphery of said chamber adjacentthe top, a separator having spaced walls forming an inner and an outerpassage, said outer passage being concentric with said inner passage,said inner passage having rotational vanes therein, a riser forpulverulent material extending downwardly into said inner passage,funnel-like member within said passage beneath said riser, a generallyhorizontal tangential gaseous fluid inlet pipe in said inner passagepositioned exteriorly of said funnel-like member, said inlet pipeimparting a motion to a gaseous fluid passing therethrough in adirection concurrent to the direction of motion imparted by said vanes,a screw conveyor for feeding material to said feed jet, said screwconveyor being connected to the lower portion of said inner passage,whereby a flow of fresh said material including material rejected bysaid separator is jetted against said bafile, guided by said cusps intosaid grinding jets, ground and the pulverulent material separated insaid separator.

3. In apparatus for pulverizing and separating material, an impactpulverizing section comprising, a substantially unconfined impactgrinding chamber, a plurality of opposed generally horizontal grindingejectors adjacent the bottom of said chamber, said grinding ejectorsbeing directed toward a common intersection, a feeding ejector for saidmaterial directed toward said common intersection and adapted to supplymaterial to said chamber, a bailie interposed between said grindingejectors and said feeding ejector, said bafile further being above andcovering said common intersection, a series of pairs of upstandinggenerally outwardly extending vanes on the side of said bafile away fromsaid grinding ejectors and forming outwardly extending channels, saidchannels being open at both ends and having the delivery end of eachthereof adjacent the intake zone of a respective grinding ejector, andan uptake from said chamber, whereby material jetted into said chamber bsaid feeding ejector is guided toward said grinding ejectors by saidchannels.

4. In apparatus for pulverizing and separating material, a separatorcomprising spaced walls forming an outer passage and a concentric innerpassage, said passages being opened into each other adjacent the topsthereof, spaced opposed vanes extending from the interior wall of saidouter passage into said inner passage and curved in the same directionabout the center of said inner passage to define said opening and impartrotation in said direction to said material, a riser for pulverulentmaterial of a predetermined particle size extending downwardly throughsaid opening, an inverted generally inwardly and downwardly extendingmember in said inner passage beneath the lower end of said riser, and agenerally horizontal and tangential gaseous fluid inlet pipe in saidinner passage exteriorly of said member, said inlet pipe impartingmotion to the gaseous fluid passing therethrough in the said direction,whereby pulverulent material of greater particle size may be removedthrough said riser.

5. In apparatus for impact pulverizing and separating material, aseparator comprising spaced walls forming an outer passage and aconcentric inner passage, said passages being opened into each otheradjacent the tops thereof, spaced opposed vanes extending from theinterior wall of said outer passage into said inner passage and curvedin the same direction about the center of said inner passage to definesaid openin and impart rotation in said direction to said material, ariser for pulverulent material of a predetermined particle sizeextending downwardly through said opening, an inverted conical member insaid inner passage beneath the lower end of said riser, a substantiallyhorizontal and tangential gaseous fluid inlet pipe in said inner passageexteriorly of said conical member, said inlet pipe impartin motion tothe gaseous fluid passing therethrough in the said direction, and aconveyor for feeding fresh material to said apparatus, said conveyorbeing also connected to the lower end of said inner passage to receivethe heavier separated material therefrom.

6. In apparatus for impact pulverizing and separating material having animpact pulverizing chamber, a separator and feedin mechanism comprisingspaced walls forming an outer passage and a concentric inner passage,said passages being opened into each other adjacent the tops thereof,spaced opposed vanes extending from the interior wall of said outerpassage into said inner passage and curved in the same direction aboutthe center of said inner passage to define said opening and impartrotation in said direction to said material, a riser for pulverulentmaterial of a predetermined particle size extending downwardly throughsaid opening, an inverted conical member in said inner passage beneaththe lower end of said riser, a substantially horizontal and tangentialgaseous fluid inlet pipe in said inner passage exteriorly of saidconical member, said inlet pipe imparting motion to the gaseous fluidpassing therethrough in the said direction, a feeding jet for supplyingmaterial to said chamber, said jet having an inspiration zone, a screwconveyor for feeding material to said inspiration zone, a conduit forsupplying fresh material to said screw conveyor, a conduit connectingsaid screw conveyor intermediate the ends thereof with said innerpassage, whereby separated material heavier than said pulverulentmaterial of a predetermined particle size is returned to said screwconveyor for admixture with said fresh material before return to saidchamber.

ALFONSE M. ANDRIES.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,498,181 Lindsay June 17, 19241,675,941 Lindsay July 3, 1928 1,847,009 Kollbohm Feb. 23, 19321,897,195 Howden Feb. 14, 1933 1,935,344 Andrews Nov. 14, 1933 1,953,058Andrews Apr. 3, 1934 2,111,663 Graem'iger Mar. 22, 1938 2,236,548 ProutyApr, 1, 1941 FOREIGN PATENTS Number Country Date 509,866 Germany Oct.13, 1930

